I do most of my reading of books purchased from Amazon on my iPad, but there are times where my laptop and desktop Mac would be just dandy for catching up on my non dead-tree efforts.
Amazon has released a new version of Kindle for Mac, and it brings the Mac version up to feature parity with the iOS versions. The new version includes these capabilities:
Add, edit or delete notes and highlights
Search for words or phrases in a book
Multi-column text is now supported
The overall look and feel are improved and a bit more contemporary
The update is free of course, and a quick download. I'd like to use the Apple iBookstore more often,